How to embed replit in iframe dynamically?

I'm trying to embed replit here https://jsfiddle.net/69ajeskL/2/ It doesn't work why ?

html:

<div id="placeHolder">
</div>

js:

let placeHolder = document.getElementById('placeHolder');
let iframe = document.createElement('iframe');
placeHolder.appendChild(iframe);

iframe.src = "https://replit.com/@SilkyS/HelloWorld?v=1";